Diastereoselective Trifluoromethylation of Chiral α,β‐Unsaturated N‐tert‐Butanesulfinyl Ketimines with Ruppert‐Prakash Reagent: Asymmetric Synthesis of α‐Tertiary Trifluoromethyl Allylic Amines.

Abstract: The diastereoselective trifluoromethylation of chiral α,β‐unsaturated N‐tert‐butanesulfinyl ketimines with Ruppert‐Prakash reagent (TMSCF3) has been attained, which provided a convenient and straightforward method for the asymmetric synthesis of structurally diverse α‐tertiary trifluoromethyl allylic amines in high yields and with excellent diastereoselectivities (dr up to > 99:1). The stereochemical outcome of the present diastereoselective trifluoromethylation of the α,β‐unsaturated N‐tert‐butanesulfinyl ketimines suggested that a cyclic six‐membered transition state is involved in the reaction, which is remarkably different from that of the trifluoromethylation of N‐tert‐butanesulfinyl aldimines. [ABSTRACT FROM AUTHOR]